COMPARISON OF NEOTROPICAL AND PALiEOTROPICAL 



INSECT FAUNAE 



By C. F. Baker 



Dean, College of Agriculture, University of the Philippinet 



Students of certain groups of insects, who have given atten- 

 tion to the faunae of both the Neotropical and the Palaeotropical 

 Regions, have frequently found the highest interest in compari- 

 son of the general features of these faunas as related to groups 

 well represented in both. In certain groups of insects the Neo- 

 tropics are characterized by great diversity of species in com- 

 paratively few distinct generic groups, and in certain groups 

 a high proportion of the genera are common North American 

 or European types. This is well exemplified in the Jassoidea, 

 and in subgenera as Tettigonia, Diabrotica, etc. On the other 

 hand, in the Palseotropics, while the number of species will prob- 

 ably prove to be even greater (due in part to fragmentation 

 of the territory into innumerable islands) , the far greater ana- 

 tomical diversity in the same groups is very conspicuous, and 

 but few European genera may be represented. Vast numbers 

 of strongly characterized generic groups have been formed 

 under the latter conditions. 



Papers recently published by Osborn 1 on the jassoid insects 

 of Brazil and Bolivia clearly illustrate this. Most of the species 

 described are referred to common North American genera and 

 seem to be typical of them. One of these genera, Idiocerus, 

 appears to be very homogeneous in structure as it is in America 

 and Europe, whereas the same group in the Far East presents 

 numberless distinct generic types of great diversity in structure. 

 Comparisons of this sort yield some highly interesting data. 



In connection with the above-mentioned papers, the following 

 changes in nomenclature are suggested, in as much as they are 

 needed for a list of the Jassoidea of the world, now about ready 

 for publication: 



'Ann. Carnegie Mus. 15 1 (March, ] 



